'Invisible gold' in bismuth chalcogenides
'Invisible gold' in bismuth chalcogenides
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DOI：
10.1016/j.gca.2009.01.006
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发表时间：
2009-04
影响因子：
5
通讯作者：
C. Ciobanu;N. Cook;A. Pring;J. Brugger;L. Danyushevsky;M. Shimizu
中科院分区：
文献类型：
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作者：
C. Ciobanu;N. Cook;A. Pring;J. Brugger;L. Danyushevsky;M. Shimizu
金的浓度已确定的LA-ICPMS铋硫族化物（碲化物和硫盐，矿物与模块化结构;硫族元素X=Te，Se和S）从27个发生。存款类型有浅成低温热液型、矽卡岩型、侵入型和造山型金。样品包括辉碲铋矿组、钾长石系列、铋硫盐（可钠锰矿、锂云母、水钠锰矿、辉铋矿和铁钠锰矿）以及伴生的阿尔泰矿。在阶段的辉碲铋矿组范围从X的金浓度<0.1 to 2527ppm. Phases in which Bi>往往包含较低的金浓度比Bi 2X 3矿物（碲铋矿和辉碲铋矿）。钴柳石和锂云母的Au含量分别高达574和3115 ppm。辉铋矿衍生物的Au浓度较低：辉铋矿中的Au浓度<2 ppm，辉铋矿中的Au浓度高达542 ppm。在我们的样品中，钠长石中Au的含量范围为<0.2 ~ 1662 ppm。LA-ICPMS曲线的平滑部分表明晶格结合的金，而曲线上的不规则性最好由金颗粒（直径为1.1 μm）的存在来解释。绘制整个数据集的Au与Ag的关系图，得到楔形分布，表明Ag支持碲化铋和硫盐中的Au吸收。在碲化物中，相关趋势表明，银（Au），连同铅，到八面体网站的层中的统计替代。在磺基盐中，Au遵循其中M1+（Ag，Cu）进入结构的偶联取代。在碲化物中，在硫族元素-硫族元素接触处存在货车德瓦耳斯间隙提供了对于从流体中清除金至关重要的p型半导体性质。这种弱键也可以作为Au（纳米）颗粒成核的位点。在磺基盐中，不同物种之间的相互替代接触也是高度可预测的，可以作为（纳米）颗粒金的陷阱。铋硫属化物中的隐形金可用于（i）识别矿田分带趋势，（ii）区分“熔融”和“流体驱动”清除，以及（iii）解释置换和再活化过程。铋硫属化物有可能成为贫硫化物Au体系中的重要Au载体，例如，如果平均Au浓度足够高且矿物足够丰富，则会对总体Au预算产生影响。
Gold concentrations have been determined by LA-ICPMS in bismuth chalcogenides (tellurides and sulfosalts, minerals with modular structures; chalcogen X=Te, Se, and S) from 27 occurrences. Deposit types include epithermal, skarn, intrusion-related and orogenic gold. The samples comprised minerals of the tetradymite group, aleksite series, bismuth sulfosalts (cosalite, lillianite, hodrushite, bismuthinite, and aikinite), and accompanying altaite. Gold concentrations in phases of the tetradymite group range from <0.1 to 2527ppm. Phases in which Bi>X tend to contain lower gold concentrations than Bi2X3minerals (tellurobismuthite and tetradymite). Cosalite and lillianite contain Au concentrations ranging up to 574 and 3115ppm, respectively. Bismuthinite derivatives have lower Au concentrations: <2ppm in bismuthinite and up to 542ppm in aikinite. In our samples, Au concentrations in altaite range from <0.2 to 1662ppm. Smoother parts of the LA-ICPMS profiles suggest lattice-bound gold, whereas irregularities on the profiles are best explained by the presence of gold particles (⩽1μm in diameter). Plotting Au vs. Ag for the entire dataset gives a wedge-shaped distribution, suggesting that Ag underpins Au uptake in both bismuth tellurides and sulfosalts. In the tellurides, correlation trends suggest statistical substitution of Ag(Au), together with Pb, into the octahedral site in the layers. In sulfosalts, Au follows coupled substitutions in which M1+(Ag, Cu) enters the structure. In tellurides, the presence of van der Waals gaps at chalcogen–chalcogen contacts provides for p-type semi-conductive properties critical for gold scavenging from fluids. Such weak bonds may also act as sites for nucleation of Au (nano)particles. In sulfosalts, contacts between different species that replace one another are also highly predictable to act as traps for (nano)particulate gold. Invisible gold in Bi-chalcogenides is useful to (i) identify trends of orefield zonation, (ii) discriminate between ‘melt’ and ‘fluid-driven’ scavenging, and (iii) interpret replacement and remobilisation processes. Bismuth chalcogenides have the potential to be significant Au carriers in sulfide-poor Au systems, e.g., intrusion-related gold, with impact on the overall Au budget if mean Au concentrations are high enough and the minerals are sufficiently abundant.